<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <!-- CSS3为我们提供了背景颜色半透明的效果。
    background:rgba(0,0,0,0.3); -->
    <style>
      body {
        background: url(D:/html/vscode/image/农主页背景.jpg) no-repeat fixed top
          center;
      }
      div {
        width: 300px;
        height: 300px;
        background: rgba(0, 0, 0, 0.3);
      }
    </style>
  </head>
  <body>
    <div></div>
  </body>
</html>
